I've had a USB hard drive connected to my MBP for over a year now (set up for time machine and some extra storage), but I'd been traveling the last 3 weeks and didn't bring the drive with me. When I got back the other day I plugged it in but it didn't show up in finder. It also does not show up in disk utility, and when I got to system info, and look at the USB ports, it's not showing anything. The drive is on and I can feel it spinning, but it's just not being connected to the computer. I updated to 10.5.6 while I was away, if that means anything. I tried restarting, turning the drive on and off, plugging and unplugging the drive, switching USB ports. The only thing I haven't tried is switching cables, but that could be difficult since i don't have another. Is there anything else it could be?